Observer variabilities of radiological classifications of calcified deposits in calcifying tendinitis of the shoulder

The radiological morphology of calcified deposits in calcifying tendinitis of the shoulder is classified according to Patte and Goutallier and according to Mole et al. The results of these classifications influence the choice of therapeutic procedures. In this study, the intraoberserver reproducibility and interobserver reliability of these classifications were determined. Plain anteroposterior radiographs of shoulders from 100 patients with symptomatic calcified deposits of the rotator cuff were classified according to the criteria of Patte and Goutallier as well as to the criteria of Mole et al, by six independent observers, twice within four months. The kappa values of intraoberserver reproducibility and interobserver reliability were calculated. Classification of Patte and Goutallier: intraoberserver reproducibility, mean kappa value 0.458 (standard deviation 0.098); interobserver reliability, mean kappa values 0.4 (first test) and 0.354 (second test). Classification of Mole et al: intraoberserver reproducibility, mean kappa value 0.402 (standard deviation 0.092); interobserver reliability, mean kappa values 0.239 (first test) and 0.191 (second test). Both classifications demonstrated a satisfactory to sufficient intraobserver reproducibility. The classification of Patte and Goutallier showed a satisfactory interobserver reliability, whereas the classification of Mole et al had a satisfactory to insufficient interobserver reliability. Studies dealing with both classifications should therefore be interpreted carefully.